WO2019052640A1

WO2019052640A1 - Operating a permanently excited synchronous machine

Info

Publication number: WO2019052640A1
Application number: PCT/EP2017/073005
Authority: WO
Inventors: Hauke NANNEN; Heiko Zatocil
Original assignee: Siemens Aktiengesellschaft
Priority date: 2017-09-13
Filing date: 2017-09-13
Publication date: 2019-03-21
Also published as: BR112020004974A2; CN111316561A; DE112017008030A5; CN111316561B

Abstract

The invention relates to a method for operating a permanently excited synchronous machine (1), which has a stator (2) having a stator winding, a rotor (3) and a thyristor controller (4) for controlling phase currents (iu, iv, iw) of the stator winding. In the method, at least two terminal voltages of the synchronous machine (1) are continually sensed. To start the synchronous machine (1), the stator winding is energized with at least one current pulse. After each current pulse, it is checked whether a voltage characteristic value formed from the terminal voltages exceeds a specified voltage threshold value. As soon as the voltage characteristic value exceeds the voltage threshold value, the synchronous machine (1) is operated in that, repeatedly, the present pole wheel angle (φ) is determined by using the sensed present terminal voltages, a present optimal firing angle for the synchronous machine (1) is calculated by using the present pole wheel angle (φ), and the thyristor controller (4) is controlled in accordance with the present optimal firing angle.

Description

description

The invention relates to a method for operating a permanent-magnet synchronous machine which has a stator with a stator winding, a rotor and a thyristor for setting phase currents of the stator winding. Three-phase machines are classified according to IEC 60034 according to their efficiency in different energy efficiency classes. Especially in the lower power range up to about 20 kW, specifications for efficiencies of high-efficiency ^motors (IE 4) are difficult to meet. Therefore, the use of permanent magnets in the rotor is increasingly sought, in particular the use of permanent magnet synchronous machines. Although this type of machine allows high energy efficiency levels, but the launch and operation of the Maschi ^¬ nen of this type in the fixed grid is not readily possible.

In order to enable the start and operation of a permanent magnet synchronous machine on the rigid network, a damper cage can be provided in the rotor of the machine. Although a damper cage allows a safe run-up on the rigid network, but loads the feeding network very high by very high start-up currents.

DE 10 2011 085 859 AI discloses a method for operating ei ^¬ ner synchronous machine by means of a three semiconductor actuator comprehensive three-phase three-phase controller, which is connected to a three-phase network. In this case, a torque curve for the synchronous machine for a definable period of time when connecting at least two of the semiconductor plates, taking into account a phase difference between a Polrad- voltage of the synchronous machine and a mains voltage of the

Three-phase network, a speed of the rotor of Synchronma ^¬ machine, a stator of the synchronous machine and a Pha ^¬ senlage the three-phase network precalculated. Based on the Out calculation, a switching time is determined to which the at least two semiconductor plates are turned on. However, this method requires the current rotor angle and the ac speed of the synchronous machine, so that the synchronous machine must be equipped with a corresponding encoder system for detecting the Polradwinkels and the speed.

The patent application with the application number

PCT / EP2016 / 074880 discloses a method for aligning ei ^¬ ner three-phase machine in which an optimum ignition angle is determined in a first step, in a second step, a first alignment using the determined optimum ignition angle is carried out, and in a third step, a plausibility check of Orientation of the rotor is performed by the rotor is applied to the previously determined firing angle in another direction. To align the rotor according to this method usually takes several seconds. After aligning the runner, the machine can be started. By Reg ^¬ processing of the rotor, the rotor is rotated in a defined initial position to determine a first ignition to start the engine. For starting, for example, a method known from the patent application with the application number PCT / EP2016 / 077201 can be used. In this case, the rotor is rotated from the known initial position with a maximum torque by means of ignition of thyristors, a voltage induced by the rotation of the rotor is measured, and an optimum ignition angle of the synchronous machine is determined. This procedure allows one

Starting the machine without a rotary encoder system, however, provides for alignment of the rotor prior to starting.

The invention has for its object to provide a method for operating a permanent-magnet synchronous machine, which is improved in particular with respect to the time required to start the synchronous ^machine and without a rotary encoder ^¬ system for detecting the Polradwinkels manages. The object is achieved by the features of claim 1. An ^¬ .

Advantageous embodiments of the invention are the subject of the dependent claims.

In the inventive method for operating a permanent-magnet synchronous machine comprising a stator having a stator winding, a rotor and a thyristor for setting of phase currents of the stator, at least two terminal voltages of the ^synchronous machine are recorded continuously. To start the synchronous machine, the stator winding is energized with at least one current pulse. After each current pulse is checked whether a from the Klemmenspannun ^¬ gen formed voltage characteristic value, for example a maximum of the sums of the detected terminal voltages or a magnitude of a voltage space vector is formed from the terminal voltages, a predetermined voltage threshold over-writing ^¬ tet, in which determined the angular displacement using the terminal voltages is. As soon as the voltage characteristic value exceeds the voltage threshold, the ^synchronous machine is operated by the then current rotor displacement is repeated using the respective detected current terminal voltages determined using the per ^¬ weils current load angle a respectively current optimum ignition angle is calculated for the synchronous machine and the Thyristor is driven according to the current optimal ignition angle. The stator winding of a synchronous machine is understood here to mean a three-phase stator winding, that is to say the entirety of the stator phase windings.

The invention thus provides to detect terminal voltages of a permanent-magnet synchronous machine and to determine the Polradwinkel of the rotor of the synchronous machine using the detected terminal voltages. In operation, the Syn ^¬ chronmaschine the rotor angle is repeatedly determined and using the current load angle a each optimum ignition angle is calculated, with which a Thyris ^¬ torsteller to sites of phase currents of the stator winding of the synchronous machine is driven. This allows advantageous way ^¬ omitted wheel angle and then computing the optimal ignition angle an expensive rotary encoder system for detecting the pole.

Furthermore, the invention provides, for starting the synchronous machine, to energize the stator winding with current pulses until a voltage characteristic formed from the terminal voltages exceeds a predetermined voltage ^threshold , which is sufficient to determine the pole wheel angle. In this case, use is made that at least one terminal voltage usually after just a few current ^¬ pulses is large enough according to experience, to determine the load angle. A time-consuming alignment of the rotor can thereby be omitted, so that the synchronous machine can be started much faster than in a two-stage process, in which the rotor is first aligned by a defined Pol ^¬ wheel angle is adjusted. Typically, the tone wheel ^¬ angle can be determined to 100 ms from the terminal voltages in the inventive method after 10 ms, whereas the complete alignment of the rotor usually requires several seconds, so to start the synchronous machine several seconds can be saved.

Embodiments of the invention provide that at least two phase currents are detected, and that the respectively current rotor angle is determined using the detected phase currents, and / or the respective current ignition angle is calculated using the detected phase currents. These embodiments of the invention make it possible to take into account not only the terminal voltages but also the phase currents in the determination of the rotor angle and / or the optimum ignition angle. This allows the determination of the load angle verbes ^¬ sert and / or the ignition angle can be calculated as a function of the phase currents and thus further optimized. A further embodiment of the invention provides that the voltage threshold value is a minimum voltage characteristic value at which the pole wheel angle can be determined using the terminal voltages. As a result, the above-mentioned time gain when starting the synchronous machine is maximized.

A further embodiment of the invention provides that a torque window and a phase current window are specified and the respective current optimum ignition angle is a Zündwin ^¬ angle, in which acting on the rotor torque within ^¬ within the torque window and each phase current of the stator winding within the phase current window lies. This embodiment of the invention advantageously prevents too high a torque or too high a phase current from overloading the synchronous machine or a power network connected thereto and consumers connected thereto too much.

A further embodiment of the invention provides that a current space vector of a current pulse is changed with respect to the current ^space vector of the preceding current pulse if the voltage ^value does not exceed the voltage ^threshold value. In particular, the current space vector of each current pulse can be changed relative to the current space vector of the current pulse preceding it, as long as the voltage value does not exceed the voltage threshold. In the change ^¬ tion of the current space pointer successive current pulses, the current space pointer is rotated, for example in a rotational direction of a rotating field of the synchronous machine. Further, when the current space vector changes, it becomes sequential

Current pulses of the current space pointer, for example, rotated by 60 degrees or a multiple of 60 degrees. By this Ausgestaltun ^¬ developments of the invention can be prevented that a plurality of current pulses are generated, which have no or only a small rotation of the rotor be Farming ^¬ ken because of the space vector directions of the current space vector and the instantaneous position of the rotor. As a result, the starting of the synchronous machine is further accelerated. A further embodiment of the invention provides that a maximum number of pulses of current pulses is predetermined and the current supply to the stator winding is interrupted by current pulses when the number of current pulses reaches the maximum number of pulses without the voltage characteristic ^value exceeding the voltage threshold value. A further embodiment of the invention provides that a maximum number of changes is predetermined and the stator winding is interrupted with current pulses when the number of changes in the current space vectors of successive current pulses reaches the maximum number of changes without the voltage characteristic value exceeding the voltage threshold value. These embodiments of the invention take into account an error case in which the synchronous machine, for example due to a defect or malfunction, can not be started. In such a case, the method is aborted when the number of current pulses reaches a predetermined maximum number of pulses and / or the number of changes in the current space pointers of successive current pulses reaches a predetermined maximum number of changes.

A permanent magnet synchronous machine according to the invention comprises a stator with a stator winding, a rotor, a thyristor for setting phase currents of the stator winding, a voltage measuring device for detecting at least two terminal voltages of the synchronous machine and a control unit for driving the Thyristorstellers according to the inventive method. The advantages of such a synchronous machine result from the abovementioned advantages of the method according to the invention.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they will be achieved, will become clearer and more clearly understood in connection with the following description of exemplary embodiments which will be described in detail in conjunction with the drawings. Showing: a circuit diagram of a permanent-magnet synchronous machine, a flowchart of a method for operating a permanent-magnet synchronous machine, a time profile of phase currents of a stator winding a permanent magnet synchronous machine, a time profile of a Polradwinkels a rotor of a permanent-magnet synchronous machine.

1 shows a circuit diagram of a permanent magnet synchronous machine 1. The synchronous ^machine 1 comprises a Sta ^¬ tor 2 with a (not shown) three-phase stator winding, a rotor 3, a thyristor 4 for setting phase currents iu, i _v , i of the stator winding and a STEU ^¬ ereinheit 5 for driving the thyristor unit 4. the thyristor unit 4 has a Thyristorenpaar 6, 7, 8 of two antiparallel-connected thyristors Al, A2, Bl, B2, Cl, C2 for each phase U, V, W of the stator winding. The ignition electrodes of the thyristors AI, A2, B1, B2, C1, C2 are connected to the control unit 5, from which the ignition signals required to ignite the thyristors AI, A2, B1, B2, C1, C2 are provided. By igniting the thyristors AI, A2, B1, B2, C1, C2 assigned to a phase U, V, W, a phase current iu, iv, i of this phase U, V, W of the stator winding is generated. The thyristors AI, A2, B1, B2, C1, C2 of a phase U, V, W turn themselves off when the phase current iu, i _v , i of this phase U, V, W becomes zero or be the ^same Sign changes. The control unit 5 is adapted to at ^¬ control the thyristor controller 4 according to the closer described with reference to Figure 2 method. For example, the control unit 5 is implemented as a programmable microcontroller that is programmed to execute the method. Figure 2 shows a flow chart of a method for Operator Op ben ^¬ a permanently excited synchronous machine 1. In the process continuously at least two terminal voltages of the synchronous machine 1 are detected. Furthermore, method steps S1 to S7 described below are executed.

In a first method step S1, the stator winding of the stator 2 is supplied with a current pulse. For this purpose, the thyristors are Al, A2, Bl, B2, Cl, C2 of two phases, ignites U, V W Ge, so that the phase currents iu, _iv, iw of the phases be ^¬ contract excessively are the same size, but have opposite signs to each other , The thyristors AI, A2, B1, B2, C1, C2 of the third phase U, V, W are not ignited, so that the third phase current iu, i _v , i is zero.

After the first process step Sl, that is, after the Ab ^¬ sound of the current pulse or after the amount of each phase current iu, i has fallen below a predetermined current threshold value _v, i or the amount of a current space vector is formed from the phase currents iu, iv, iw is the method continued with a second method step S2.

In the second method step S2, it is checked whether a voltage characteristic formed from the terminal voltages, for example a maximum of the amounts of the detected terminal voltages or an amount of a voltage space vector formed from the terminal voltages, exceeds a predetermined voltage threshold at which a rotor angle φ of the rotor 3 is lower than Use of the terminal voltages can be determined. If the check reveals that the voltage characteristic value does not exceed the voltage threshold, the Ver ^¬ will proceed to a third step S3 continues, otherwise the process proceeds to a fifth method is ^¬ step S5 continued.

In the third step S3, the value of a count ^¬ variable which counts the pulses generated current for energizing the stator winding, is incremented by one. If the value of Count variables then reaches a predetermined maximum number of pulses, the process is aborted in a fourth procedural ^¬ step S4. Otherwise, after the third method step S3, the first method step S1 is executed again.

In the first four method steps S1 to S4, therefore, the stator winding is energized with current pulses until the voltage characteristic value exceeds the predetermined voltage threshold value or the number of current pulses reaches the predetermined maximum number of pulses. In the case that the voltage characteristic value exceeds the voltage threshold value, the rotor 3 rotates fast enough to determine the rotor angle φ from the detected terminal voltages, so that the method can be continued with the fifth method step S5. The termination of the process in the case that the number of Strompul ^¬ se reaches the predetermined maximum number of pulses is vorgese ^¬ hen, to respond to an error case where the synchronous machine 1 can not be started.

The further steps S5 to S7 correspond to the method known from the patent application with the application number PCT / EP2016 / 077201 for operating the synchronous machine 1 and are therefore not described in detail here.

In the fifth method step S5, the actual rotor angle φ is determined using the detected current terminal voltages. After the fifth method step S5, the method is continued with the sixth method step S6.

In the sixth method step S6, a respective current optimum ignition angle for the synchronous machine 1 is calculated using the current rotor angle φ. The optimum ignition angle is an ignition angle, in which an acting on the rotor 3 torque is within a predetermined torque ^¬ window and each phase current iu, i _v, i ei is within ^¬ nes predetermined phase current window. After the sixth Step S6, the process with the seventh Ver ^¬ drive step S7 is continued.

In the seventh step S7, the Thyristorstel- 1 Series 4 being ^¬ controls according to the current optimum ignition angle. After the seventh step S7, the Ver ^¬ will proceed to the fifth step S5 continued.

FIGS. 3 and 4 illustrate, by way of example, the method steps S1 to S3 and S5. FIG. 3 shows a profile of the phase currents iu, i _v , iw as a function of a time t with two successive current pulses with which the stator winding is energized. In the example shown, the thyristors AI, A2, B1, B2 of the phases U and V are ignited to generate the current pulses. Figure 4 shows corresponding Ver ^¬ runs of the load angle φ and of a determined using the detected current depending ^¬ weils terminal voltages load angle cp _c. In the case shown in FIGS. 3 and 4, the rotor 3 does not rotate before the first current pulse, so that the pole wheel angle φ remains constant until the first current pulse. Through the first current pulse of the rotor is set in Dre ^¬ hung 3 and rotates between the first current pulse and the second current pulse due to its inertia with Annae ^¬ hernd same angular velocity further, thereby Terminal voltages are induced. However, this angular velocity is not yet sufficient to determine the pole wheel angle φ using the respectively detected actual terminal voltages induced by the rotor rotation, that is, between the first current pulse and the second current pulse the voltage characteristic ^value does not yet exceed the voltage threshold value , The rotor 2 is further accelerated by the second current pulse, so that the angular velocity of the rotation of the rotor 3 after the second current pulse is sufficient to determine the rotor angle φ using the detected terminal voltages induced by the rotor rotation, that is , after the second current pulse of the voltage characteristic value exceeds the voltage threshold value ^¬. FIG. 4 also shows that the method described using determined clamping voltages detected rotor angle cp _c very well with the actual Polradwinkel φ coincides. In the example shown in FIGS. 3 and 4, the rotor angle φ can already be determined after approximately 40 ms using the detected terminal voltages.

The method described above with reference to FIG. 2 can be extended in various ways. For example, in a repeated implementation of the first method step Sl, a current space vector of the current pulse can be changed with respect to the current space vector of the preceding current pulse. In particular, the current space vector can be rotated relative to the current space vector of the preceding current pulse in a direction of rotation of a rotating field of the synchronous machine 1, for example by 60 degrees or a multiple of 60 degrees. The rotation of the current space vector may be provided at ^¬ play, when a predetermined pulse number of consecutive current pulses is carried out with current space vectors same space vector direction. It can also be provided that the current space vector of each current pulse is rotated relative to the current space vector of the current pulse preceding it. By these embodiments, it can be prevented that a plurality of current pulses are generated with Stromraumzeigern an unfavorable or ineffective Raumzeigerrichtung.

In the third step S3 may be appropriately pre see ^¬ that the method is aborted in the fourth step S4, if the number of changes of the current space vector successive current pulses reaches a predetermined maximum variation number.

Furthermore, it can be provided that at least two phase currents iu, i _v , iw are detected and in the fifth method step S5 the rotor angle φ is determined using the detected phase currents iu, i _v , i and / or in the six-phase mode. Step S6, the ignition angle is calculated using the detected phase currents iu, i _v , i -w. While the invention has been further illustrated and described in detail by way of preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims

claims

A method of operating a permanent magnet synchronous machine (1) comprising a stator (2) having a stator winding, a rotor (3) and a thyristor (4) for setting phase currents (iu, i _v , i) of the stator winding,

- continuously at least two terminal voltages of the synchronous machine (1) are detected,

- To start the synchronous machine (1), the stator winding is energized with at least one current pulse,

- is checked after each current pulse, whether formed of the terminals ^¬ voltages voltage characteristic value exceeds a predetermined voltage threshold value at which a Polradwin- angle (φ) of the rotor (3) using the terminal voltages can be determined, and

- as soon as the voltage characteristic value exceeds the voltage threshold, the synchronous machine (1) is operated by repeatedly using the respective detected instantaneous terminal voltages of the respective current load angle (φ) it ^¬ averages is, using the current tone wheel ^¬ angle (φ) a respective current optimal ignition angle for the synchronous machine (1) is calculated and the thyristor ^¬ actuator (4) is driven according to the respective current optimum ignition angle.

2. The method according to claim 1,

characterized in that at least two Phasenströ ^¬ me (iu, i _v , iw) are detected and the respective current Polradradwinkel (φ) using the detected phase currents (iu, i _v , iw) is determined.

3. The method according to claim 1 or 2,

characterized in that at least two Phasenströ- me (iu, iv, iw) are detected and the current actual ^Zünd¬ angle using the detected phase currents (iu, iv, i _w ) is calculated.

4. The method according to any one of the preceding claims, characterized in that the voltage threshold ei is a minimum voltage characteristic value, wherein the Polradwinkel

can be determined using the terminal voltages.

5. The method according to any one of the preceding claims, characterized in that a torque window and a phase current window are specified and the respective current optimum ignition angle is a firing angle at which on the rotor (3) acting torque is within the ^{Drehmomentfens ¬} ters and each phase current (iu, i _v , i) of the Statorwick ^¬ ment within the phase current window is located.

6. The method according to any one of the preceding claims, characterized in that a current space pointer of a current pulse with respect to the current space pointer of the preceding

Current pulse is changed when the voltage characteristic does not exceed the voltage threshold.

7. The method according to any one of the preceding claims, characterized in that the current space pointer of each current pulse is changed relative to the current space pointer of the preceding current pulse, as long as the voltage characteristic does not exceed the voltage threshold.

8. The method according to claim 6 or 7,

characterized in that in the change of the current space pointer successive current pulses of the current space pointer in a rotational direction of a rotating field of the synchronous machine (1) is rotated.

9. The method according to any one of claims 6 to 8,

characterized in that when changing the current space pointer successive current pulses of the current space pointer is rotated by 60 degrees or a multiple of 60 degrees.

10. The method according to any one of the preceding claims, characterized in that a maximum change number is specified and the energizing of the stator winding is stopped with current pulses when the number of changes of the current space pointer successive current pulses reaches the maximum change number without the voltage characteristic value exceeds the voltage threshold.

11. The method according to any one of the preceding claims, characterized in that a maximum number of pulses of

Current pulses is specified and the energizing of the stator winding is stopped with current pulses when the number of current pulses reaches the maximum number of pulses without the voltage characteristic value exceeds the voltage threshold.

12. The method according to any one of the preceding claims, characterized in that the voltage characteristic is a Maxi ^¬ mum the amounts of the detected terminal voltages or an amount of a voltage space vector formed from the terminal voltages.

13. Permanent magnet synchronous machine (1), comprising

a stator (2) with a stator winding,

a rotor (3),

a thyristor (4) for setting phase currents (iu, i _v , i) of the stator winding,

- A voltage measuring device for detecting at least two terminal voltages of the synchronous machine (1), and

- A control unit (5) for controlling the Thyristorstel ^¬ lers (4) according to the method according to any one of the preceding claims.